Lecture Summary

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Week 1- week 5

(Gums and stabilizers)


Hydrocolloid

• Range of polysaccharides and protein
• Also know as water soluble gums, stabilisers

Functions:
primary--->

• Thickening agent
• Gelling or texturizing agents

Secondary--->

• Stabilisation of emulsion
• Suspension of particulates
• Control of cystallisation
• Encapsulation

Structure of hydrocolloid

High degree of substitution, faster to hydrate
Low degree of substitution,slower to hydrate

High degree of polymerization,high viscosity-->slow to hydrate
Lower degree of polymerization,low viscosity-->faster to hydrate

Factors affect gum properties

• Molecular weight
• Monosaccharide composition
• Type of side chain
• Number of side chain
• Distribution of side chain

List of hydrocolloid:

• (Gelling Gums)

• Pectin
• Carrageenan
• Alginate
• Gelatin
• Agar
• Gellan
• Konjac Glucomannan
• Methyl cellulose ( hot)

• (Thickening Gums)

• Locust bean gum (LBG)
• Tara gum
• Gum Arabic
• Gum karaya
• Xantan gum
• Guar gum
• Tragacanth
• Propylene glycol alginate
• Carboxymethycellulose

Pectin

Raw material which are source of pectin:
Citrus peel

Apple pomace

Sugar beet chips

Natural form is called protopectin ( where they are still in primary form and not yet extracted)

Types of pectin
High methoxyl pectin (HMP)---> degree of esterification>50%
Low methoxyl pectin (LMP)--->degree of esterification<50%
DE=Galacturonic acid partially esterified as methyl esters.

HMP

• To form gel, the soluble solid content must be 5-58% and PH 2.8-3.8 in jam and jellies.
• its a rapid set(DE 77) & slow set(DE 58)
• Rapid set- widely used in jams with whole fruits(marmalade) -->to ensure uniform distribution
• Acidic fruit( blackcurrant) require slow set---> avoid premature gelation
• Not heat reversible
• Gels at high temperature and low PH
• DE high, ability to gel high

LMP

• 2 sub groups, conventional LMP, and Amidated LMP.
• Calcium ion needed for it to form gel with low solid content and PH 1-7.
• Thickening agent in yoghurt-because less calcium ion reactive than ALMP
• Assist gelation in low sugar jam and jellies-because very reactive calcium ion
• Heat reversible

Usage of pectin in food

• Jams, jellies and preservatives
• Stabilisers( in fruit juices, fruit drinks concentrated)
• In fermented/directly acidified dairy products
• Used in baked products-cake glazing,fruit fillings (confectioneries)
• Soft drinks and sherbets
• Ketchup,sauces,and chutneys

Carrageenan

Extracted of red algae, the Carrageenan structure composed of linear galactan polysaccharides that have sulfate(negative charge).

3 types---> kappa , Lambda, and Iota

• Kappa and Iota Carrageenan have ability to form thermoreversible gels upon cooling of hot aqueous solution contain cation example potassium ion.
• Lambda does not form gel

(Carrageenan versatile as food additives, because they are capable of binding water,promoting gel formation, act as thickener and stabilizing agents as well as improve the palatibility and food's appearance)

Food examples that use carrageenan




Desserts, gels, ice-cream, chocolate, milk, canned foods.

Alginate

• Originated from brown seaweed
• Contain D-mannuronic acid ( M block) & L-guluronic acid ( G-block)
• Solution and gelling properties of alginate can be determined from ratio of M : G and molecular weight of polymer.
• High G form strong brittle gel and good heat stability
• Can form gel in cold water with Ca ion
• Thermo-irreversible
• Will form gel with acid and alkali with divalent cation like calcium ions

Application in foods--->

1. Stabilizing effect in frozen products ( ice cream- avoid crystallization, give homogeneous breakdown)
2. Thickener in beverages ( dry mix fruit drinks- fast hydration, mouthfeel)
3. Emulsification property (propylene glycol alginate) and used as stabilizer in emulsion ( mayonnaise)
4. Fruit drink prepared with fruit pulp, ( orange crush) have sedimentation of the pulp, it can be prevented by adding sodium alginate/proopylene glycol alginate

Gum Arabic

• Derived form Acacia senegal L
• Sap exuded from the Acacia trees
• Complex structure, polysaccharide contain galactose,rhamnose,arabinopyranose,arabinofuranose,and glucoronic acid.
• Contain small amnount of protein, calcium, magnesium, and potassium.
• Dissolve easily in hot/cold water
• Least viscous and most soluble
• Use in confectionery products--> retard sugar crystallization and emulsification.

Locust bean gum

• Viscosity or stability very little affected by pH within the range of 3-11 pH
• uses are wide in ice-cream stabilization, the unusual swelling and water inhibiting qualities, as well as smooth meltdown and excellent heat-shock resistance.
• Also used in meat products, for manufacturing processed meats, they act as binding and stabilizing agent, so will result in more homogeneous product, and improved texture and quality.

Guar gum

• Linear chain of mannose, and single galactose unit attach as side chain
• more highly substituted than Locus bean gum, mean it is more soluble and hydrates fully in cold water and give high viscosity
• Non-gelling, and use as viscosity builder,stabilizer,and water binder.
• stable at pH 4-10
• Will degrade at extreme temperature and pH.

Xanthan gum

• Polysaccharides produced from carbohydrate substrate with xanthomonas campestris
• Soluble in cold water
• Produce high viscosity at low concentration
• Excellent stability of heat and pH
• Viscosity remain unchange across temperature of 0-100 degree Celsius and pH 1-13
• have pseudoplastic property> for good flavour release and mouthfeel
• Used as thickening , suspending and stabilizing effects

Cellulose derivatives

• Chemically modified cellulose
• Alkaline treatment convert cellulose to ether
• Example--> carboxymethylcellulose ( CMC), and hydroxypropylmethylcellulose ( HPMC)
• Clear solution and stable over pH 4-10
• Used as thickening, suspending, stabilizing and modify flow characteristics
• Methylcellulose (MC) and HPMC gel when heated, become liquid back when cooled
• Can reduce oil absorption
• Prevent loss of moisture
• improve adhesion of batter

Relative ranking of gum properties

• Solution clarity ( transparency)
• Gelling vs thickening
• suspension ability
• Natural vs non-natural
• Ability to stabilize protein at low pH
• Acid stability
• Relative cost per unit weight

Gelatin

• Derived from collagen ,the primary protein component , example, animal connective tissue--> bone , skin, tendon by acid or alkali treatment
• Type A--> derived from acid processed materials , example, porkskin
• Type B--> derived from alkali or lime processed materials, example, primary cattle of calf hides and ossein
• pH and temperature can cause drop in gelling properties

uses as functional ingredient--->

• High quality gels in dilute solution with clean melt in mouth texture
• High concentration, it give elastic gum like textures, that slowly dissolve in mouth
• effective emulsifying and foaming agent
• As polyelectrolyte , able to flocculate suspended molecules
• Used in jelly, yogurt, fruit juices,ice-cream and frozen produts, also gummy sweets